period or IB?!

Help?! So I thought I was pregnant, my fiancé came inside and after that we continued having unprotected sex with him finishing inside. I was getting symptoms and yesterday I started bleeding. It was super watery and bloody, no clots. Today I was standing for a long period of time and when I got home my pad was soaked, it's nothing like a regular period. It's water literally red water! Idk what's going on..i have cramps and all...anyone know what this could be?